Prevalence Of Respiratory Syncytial Virus Research Articles

Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic

Respiratory Syncytial Virus (RSV) is a leading cause of acute respiratory tract infection, with the greatest impact on infants, immunocompromised individuals, and older adults. RSV prevalence decreased substantially in the United States (US) following the implementation of COVID-19-related non-pharmaceutical interventions but later rebounded with abnormal seasonality. The biological and epidemiological factors underlying this altered behavior remain poorly defined. In this retrospective cohort study from 2009 to 2023 in Chicago, Illinois, US, we examined RSV epidemiology, clinical severity, and genetic diversity. We found that changes in RSV diagnostic platforms drove increased detections in outpatient settings post-2020 and that hospitalized adults infected with RSV-A were at higher risk of intensive care admission than those with RSV-B. While population structures of RSV-A remained unchanged, RSV-B exhibited a genetic shift into geographically distinct clusters. Mutations in the antigenic regions of the fusion protein suggest convergent evolution with potential implications for vaccine and therapeutic development.

Resurgence of respiratory syncytial virus with dominance of RSV-B during the 2022-2023 season.

Respiratory syncytial virus (RSV) is a common cause of upper and lower respiratory tract infections. This study aimed to explore the prevalence of respiratory syncytial virus (RSV) and other respiratory viruses in Bulgaria, characterize the genetic diversity of RSV strains, and perform amino acid sequence analyses of RSV surface and internal proteins. Clinical and epidemiological data and nasopharyngeal swabs were prospectively collected from patients with acute respiratory infections between October 2020 and May 2023. Real-time PCR for 13 respiratory viruses, whole-genome sequencing, phylogenetic, and amino acid analyses were performed. This study included three epidemic seasons (2020-2021, 2021-2022, and 2022-2023) from week 40 of the previous year to week 20 of the following year. Of the 3,047 patients examined, 1,813 (59.5%) tested positive for at least one viral respiratory pathogen. RSV was the second most detected virus (10.9%) after SARS-CoV-2 (22%). Coinfections between RSV and other respiratory viruses were detected in 68 cases, including 14 with SARS-CoV-2. After two seasons of low circulation, RSV activity increased significantly during the 2022-2023 season. The detection rates of RSV were 3.2, 6.6, and 13.7% in the first, second, and third seasons, respectively. RSV was the most common virus found in children under 5 years old with bronchiolitis (40%) and pneumonia (24.5%). RSV-B drove the 2022-2023 epidemic. Phylogenetic analysis indicated that the sequenced RSV-B strains belonged to the GB5.0.5a and GB5.0.6a genotypes. Amino acid substitutions in the surface and internal proteins, including the F protein antigenic sites were identified compared to the BA prototype strain. This study revealed a strong resurgence of RSV in the autumn of 2022 after the lifting of anti-COVID-19 measures, the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, and relatively low genetic diversity in circulating RSV strains.

Impact of Nonpharmaceutical Interventions during the COVID-19 Pandemic on the Prevalence of Respiratory Syncytial Virus in Hospitalized Children with Lower Respiratory Tract Infections: A Systematic Review and Meta-Analysis.

During the COVID-19 pandemic, nonpharmaceutical interventions (NPIs) were implemented in order to control the transmission of SARS-CoV-2, potentially affecting the prevalence of respiratory syncytial virus (RSV). This review evaluated the impact of NPIs on RSV-related hospitalizations in children during the lockdown (2020-2021) compared to the pre-pandemic (2015-2020) and post-lockdown (2021-2022) periods. In this systematic review and meta-analysis, we searched through PubMed, Scopus, and Web of Science for studies published in English between 1 January 2015 and 31 December 2022. Additionally, we conducted hand searches of other records published between 1 January 2023 and 22 January 2024. Our target population was hospitalized children aged 0-18 years with RSV-related lower respiratory tract infections confirmed through immunofluorescence, antigen testing, or molecular assays. We focused on peer-reviewed observational studies, analyzing the primary outcome of pooled RSV prevalence. A generalized linear mixed model with a random-effects model was utilized to pool each RSV prevalence. Heterogeneity was assessed using Cochran's Q and I2 statistics, while publication bias was evaluated through funnel plots and Egger's tests. We identified and analyzed 5815 publications and included 112 studies with 308,985 participants. Notably, RSV prevalence was significantly lower during the lockdown period (5.03% [95% CI: 2.67; 9.28]) than during the pre-pandemic period (25.60% [95% CI: 22.57; 28.88], p < 0.0001). However, RSV prevalence increased notably in the post-lockdown period after the relaxation of COVID-19 prevention measures (42.02% [95% CI: 31.49; 53.33] vs. 5.03% [95% CI: 2.67; 9.28], p < 0.0001). Most pooled effect estimates exhibited significant heterogeneity (I2: 91.2% to 99.3%). Our findings emphasize the effectiveness of NPIs in reducing RSV transmission. NPIs should be considered significant public health measures to address RSV outbreaks.

Respiratory syncytial virus among hospitalized patients of severe acute respiratory infection in Bhutan: Cross-sectional study.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections worldwide, particularly in young children. In Bhutan, respiratory disease continues to be among the top 10 diseases of morbidity for several years. This study aimed to estimate the prevalence of RSV among hospitalized patients with severe acute respiratory infection (SARI) in Bhutan. Respiratory specimens were collected from SARI patients of all ages in 2016 and 2018 following influenza surveillance guidelines. Specimens were tested for influenza and RSV, human metapneumovirus, adenovirus, and human parainfluenza virus types 1, 2, and 3 using real-time reverse-transcription polymerase chain reaction assay. Descriptive statistics were used to analyze the result in STATA 16.1. Of the 1339 SARI specimens tested, 34.8% were positive for at least one viral pathogen. RSV was detected in 18.5% of SARI cases, followed by influenza in 13.4% and other respiratory viruses in 3%. The median age of SARI cases was 3 (IQR: 0.8-21 years)years. RSV detection was higher among children aged 0-6 (Adj OR: 3.03; 95% CI: 1.7-5.39) and 7-23 months (Adj OR: 3.01; 95% CI: 1.77-5.12) compared with the children aged 5-15 years. RSV was also associated with breathing difficulty (Adj OR: 1.73; 95% CI: 1.17-2.56) and pre-existing lung disease, including asthma (Adj OR: 2.78; 95% CI: 0.99-7.8). Respiratory viruses were detected in a substantial proportion of SARI hospitalizations in Bhutan.

Respiratory Syncytial Virus: Transmission and Treatment

Respiratory Syncytial Virus (RSV), a respiratory tract infection-causing virus with a global distribution and seasonal occurrence, is the second leading cause of death in children under one year old, after malaria. The Respiratory Syncytial virus is an enveloped negative-strand RNA virus from the Paramyxoviridae family primarily transmitted by droplets of a cough or sneeze. However, kisses between infected and healthy individuals can also rapidly spread the virus, especially among children. Typically, the virus causes symptoms such as coughing, sneezing, or a fever making it visibly like other infections or conditions. Young children may have apnea and overall be irritable. Confirmation of RSV diagnosis can be done through available RSV-card tests or through RT-PCR tests. Though there is no standard treatment for RSV infection, drugs such as Ribavirin and Synagis (Palivizumab) are currently used for managing symptoms of RSV infection in areas that have access to such medications. Palivizumab is used to treat prophylaxis, the prevention of serious lower respiratory tract disease brought on by RSV in children at high risk of RSV disease, is the greatest preventative approach. Numerous clinical studies are being conducted right now to treat and prevent RSV infection. Most of the study focuses on children below the age of 5 years because they are the most vulnerable, but there is also research on the prevalence of RSV in older adults and the effects of maternal vaccination on infants through the antibodies made to fight against RSV infection. G protein, F protein, and SH protein are three crucial membrane proteins that make up the RSV structure. A vaccine containing both the F and G RSV proteins would offer more protection against RSV. The F and G protein stimulates antibody formation, which neutralizes the virus. The RSV treatment plans and vaccine trials within India, South Africa, the United States of America, and the United Kingdom show similarities and differences that could be utilized to develop a treatment plan for RSV. In the upcoming years, further research is required to produce a cheaper alternative that is accessible to all countries. This will help to establish a set, effective protocol for RSV to be used worldwide.

Epidemiology and risk factors of respiratory syncytial virus associated acute respiratory tract infection in hospitalized children younger than 5 years from Sri Lanka.

Respiratory syncytial virus (RSV) is the leading cause of acute respiratory tract infections (ARTI) and a major cause of morbidity and mortality in children worldwide. This study aimed to describe the prevalence and seasonal patterns of RSV and to determine the actual and predictive association of RSV-associated ARTI and clinical, socio-demographic, and climatic risk factors in children < 5 years. Nasopharyngeal aspirates were collected from 500 children < 5 years admitted to the Kegalle General Hospital, Sri Lanka between May 2016 to July 2018. RSV and RSV subtypes were detected using immunofluorescence assay and real time RT-PCR, respectively. Descriptive and inferential statistics were done for the data analysis using Chi-square, Fisher's exact, Kruskal-Wallis test, and multiple binary logistic regression in the statistical package for social sciences (SPSS), version 16.0. Prevalence of RSV-associated ARTI was 28% in children < 5 years. Both RSV subtypes were detected throughout the study period. RSV-B was the dominant subtype detected with a prevalence of 72.14%. RSV infection in general caused severe respiratory disease leading to hypoxemia. Compared to RSV-B, RSV-A infection had more symptoms leading to hypoxemia. Factors increasing the risk of contracting RSV infection included number of people living (n > 6), having pets at home and inhaling toxic fumes. The inferential analysis predicts RSV infection in children < 5 years with ARTI, with a 75.4% probability with clinical and socio-demographic characteristics like age < 1 year, fever for > 4 days, cough, conjunctivitis, stuffiness, fatigue, six or more people at home, having pets at home and inhaling toxic fumes. Climatic factors like increases in temperature (°C), wind speed (Km/h), wind gust (Km/h), rainfall (mm) and atmospheric pressure (mb) showed a strong correlation with the RSV infection in children.

Leveraging Influenza Virus Surveillance From 2012 to 2015 to Characterize the Burden of Respiratory Syncytial Virus Disease in Canadian Adults ≥50 Years of Age Hospitalized With Acute Respiratory Illness.

Respiratory syncytial virus (RSV) disease in older adults is undercharacterized. To help inform future immunization policies, this study aimed to describe the disease burden in Canadian adults aged ≥50 years hospitalized with RSV. Using administrative data and nasopharyngeal swabs collected from active surveillance among adults aged ≥50 years hospitalized with an acute respiratory illness (ARI) during the 2012-2013, 2013-2014, and 2014-2015 influenza seasons, RSV was identified using a respiratory virus multiplex polymerase chain reaction test to describe the associated disease burden, incidence, and healthcare costs. Of 7797 patients tested, 371 (4.8%) were RSV positive (2.2% RSV-A and 2.6% RSV-B). RSV prevalence varied by season from 4.2% to 6.2%. Respiratory virus coinfection was observed in 11.6% (43/371) of RSV cases, with influenza A being the most common. RSV hospitalization rates varied between seasons and increased with age, from 8-12 per 100 000 population in adults aged 50-59 years to 174-487 per 100 000 in adults aged ≥80 years. The median age of RSV cases was 74.9 years, 63.7% were female, and 98.1% of cases had ≥1 comorbidity. Among RSV cases, the mean length of hospital stay was 10.6 days, 13.7% were admitted to the intensive care unit, 6.4% required mechanical ventilation, and 6.1% died. The mean cost per RSV case was $13 602 (Canadian dollars) but varied by age and Canadian province. This study adds to the growing literature on adult RSV burden by showing considerable morbidity, mortality, and healthcare costs in hospitalized adults aged ≥50 years with ARIs such as influenza.

Epidemiological Characteristics of Respiratory Syncytial Virus Infection Among Hospitalized Children With Acute Respiratory Tract Infections From 2014 to 2022 in a Hospital in Hubei Province, China: Longitudinal Surveillance Study.

Longitudinal studies characterizing the epidemic trend of respiratory syncytial virus (RSV) in Hubei Province are scarce. We aimed to depict the dynamics of the RSV epidemic among hospitalized children with acute respiratory tract infections (ARTIs) during 2014 to 2022 in the Maternal and Child Health Hospital of Hubei Province and investigate the influence of the 2-child policy and the COVID-19 pandemic on RSV prevalence. The medical records and testing results of hospitalized children with ARTI from January 2014 to June 2022 were extracted. Nasopharyngeal samples were tested with direct immunofluorescence assay. Detection rates of RSV were categorized according to the diagnosis of patients: (1) overall, (2) upper respiratory tract infection (URTI), and (3) lower respiratory tract infection (LRTI). Poisson regression models were used to investigate the association between RSV detection rate and age, gender, or diagnosis. The detection rates of RSV before and after the implementation of the universal 2-child policy were compared using a Poisson regression model. Multiple comparisons of RSV detection rates were conducted among 3 stages of the COVID-19 pandemic using chi-square tests. Seasonal autoregressive integrated moving average was performed to predict RSV behaviors from February 2020 to June 2020 under the assumption of a non-COVID-19 scenario. Among 75,128 hospitalized children with ARTI, 11.1% (8336/75,128) were RSV-positive. Children aged <1 year had higher detection rates than older children (4204/26,498, 15.9% vs 74/5504, 1.3%; P<.001), and children with LRTI had higher detection rates than children with URTI (7733/53,145, 14.6% vs 603/21,983, 2.7%; P<.001). Among all the children, a clear seasonal pattern of the RSV epidemic was observed before 2021. Most of the highest detection rates were concentrated between December and February. The yearly detection rate of RSV remained at a relatively low level (about 8%) from 2014 to 2017, then increased to 12% and above from 2018. The highest monthly detection rate was in December 2018 (539/1493, 36.1%), and the highest yearly rate was in 2021 (1372/9328, 14.7%). There was a moderate increase in the RSV detection rate after the 2-child policy was implemented (before: 860/10,446, 8.2% vs after: 4920/43,916, 11.2%; P<.001). The largest increase, by 5.83%, occurred in children aged <1 year. The RSV epidemic level decreased sharply in the short term after the COVID-19 outbreak (detection rate before: 1600/17,010, 9.4% vs after: 32/1135, 2.8%; P<.001). The largest decrease, by 12.0%, occurred in children aged <1 year, but a rebounding epidemic occurred after 2020 (680/5744, 11.8%; P<.001). Children have been experiencing increased prevalence of RSV since 2018 based on surveillance from a hospital in Hubei Province with a large sample size. The 2-child policy might have increased the RSV prevalence, and the COVID-19 epidemic had a temporary inhibitory effect on RSV transmission. Vaccines against RSV are urgently needed.

Detection of Respiratory Syncytial Virus in Suspected Asthmatic Children by Conventional RT-PCR Assays in Kathmandu

Respiratory Syncytial Virus (RSV) is the most common causative agent for lower respiratory tract infections in children particularly in infants. At least 50% of children are infected with RSV by the age of 2 to 3 years of age. However, the diagnosis of the RSV infection and its association with risk factors for asthma in asthmatic children is not studied in Nepal. The objectives of this study were to determine the prevalence of RSV in asthmatic children. This work was a hospital based cross-sectional prospective study and conducted from September 2017 to February 2018. Ethical approval was obtained from the Institutional Review Committee (IRC) of Kanti Children’s Hospital, Maharajgunj. Suspected asthmatic children visiting the Special Asthma OPD of Kanti Children’s Hospital, Maharajgunj were selected with the help of asthma specialist using a set of inclusion criteria for asthma. A total of 32 nasal swab samples were obtained from suspected asthmatic children. Initially, samples were processed for RNA extraction. The extracted RNA was then used for cDNA synthesis followed by PCR using primers for the Nucleocapsid (N) gene of RSV. Out of total 32 samples, 9 (28%) samples were positive for the N gene of RSV. There was no significant association of different variables including age (P=0.187), sex (P=0.264), family history of asthma (P=0.115), passive smoking (P=0.88), birth weight (P=0.954), seasonality (P=0.298) and history of pneumonia (P=0.457) with the RSV infection in this study.

Nirsevimab binding-site conservation in respiratory syncytial virus fusion glycoprotein worldwide between 1956 and 2021: an analysis of observational study sequencing data

Nirsevimab is an extended half-life monoclonal antibody to the respiratory syncytial virus (RSV) fusion protein that has been developed to protect infants for an entire RSV season. Previous studies have shown that the nirsevimab binding site is highly conserved. However, investigations of the geotemporal evolution of potential escape variants in recent (ie, 2015-2021) RSV seasons have been minimal. Here, we examine prospective RSV surveillance data to assess the geotemporal prevalence of RSV A and B, and functionally characterise the effect of the nirsevimab binding-site substitutions identified between 2015 and 2021. We assessed the geotemporal prevalence of RSV A and B and nirsevimab binding-site conservation between 2015 and 2021 from three prospective RSV molecular surveillance studies (the US-based OUTSMART-RSV, the global INFORM-RSV, and a pilot study in South Africa). Nirsevimab binding-site substitutions were assessed in an RSV microneutralisation susceptibility assay. We contextualised our findings by assessing fusion-protein sequence diversity from 1956 to 2021 relative to other respiratory-virus envelope glycoproteins using RSV fusion protein sequences published in NCBI GenBank. We identified 5675 RSV A and RSV B fusion protein sequences (2875 RSV A and 2800 RSV B) from the three surveillance studies (2015-2021). Nearly all (25 [100%] of 25 positions of RSV A fusion proteins and 22 [88%] of 25 positions of RSV B fusion proteins) amino acids within the nirsevimab binding site remained highly conserved between 2015 and 2021. A highly prevalent (ie, >40·0% of all sequences) nirsevimab binding-site Ile206Met:Gln209Arg RSV B polymorphism arose between 2016 and 2021. Nirsevimab neutralised a diverse set of recombinant RSV viruses, including new variants containing binding-site substitutions. RSV B variants with reduced susceptibility to nirsevimab neutralisation were detected at low frequencies (ie, prevalence <1·0%) between 2015 and 2021. We used 3626 RSV fusion-protein sequences published in NCBI GenBank between 1956 and 2021 (2024 RSV and 1602 RSV B) to show that the RSV fusion protein had lower genetic diversity than influenza haemagglutinin and SARS-CoV-2 spike proteins. The nirsevimab binding site was highly conserved between 1956 and 2021. Nirsevimab escape variants were rare and have not increased over time. AstraZeneca and Sanofi.

Impact of the COVID-19 pandemic on the prevalence of influenza A and respiratory syncytial viruses elucidated by wastewater-based epidemiology

Since the COVID-19 pandemic, a decrease in the prevalence of Influenza A virus (IAV) and respiratory syncytial virus (RSV) has been suggested by clinical surveillance. However, there may be potential biases in obtaining an accurate overview of infectious diseases in a community. To elucidate the impact of the COVID-19 on the prevalence of IAV and RSV, we quantified IAV and RSV RNA in wastewater collected from three wastewater treatment plants (WWTPs) in Sapporo, Japan, between October 2018 and January 2023, using highly sensitive EPISENS™ method. From October 2018 to April 2020, the IAV M gene concentrations were positively correlated with the confirmed cases in the corresponding area (Spearman's r = 0.61). Subtype-specific HA genes of IAV were also detected, and their concentrations showed trends that were consistent with clinically reported cases. RSV A and B serotypes were also detected in wastewater, and their concentrations were positively correlated with the confirmed clinical cases (Spearman's r = 0.36–0.52). The detection ratios of IAV and RSV in wastewater decreased from 66.7 % (22/33) and 42.4 % (14/33) to 4.56 % (12/263) and 32.7 % (86/263), respectively in the city after the COVID-19 prevalence. The present study demonstrates the potential usefulness of wastewater-based epidemiology combined with the preservation of wastewater (wastewater banking) as a tool for better management of respiratory viral diseases.

Epidemiology and molecular characteristics of respiratory syncytial virus (RSV) among italian community-dwelling adults, 2021/22 season

BackgroundRespiratory syncytial virus (RSV) is a leading cause of acute respiratory infections worldwide. While historically RSV research has been focused on children, data on RSV infection in adults are limited. The goal of this study was to establish the prevalence of RSV in community-dwelling Italian adults and analyze its genetic variability during the 2021/22 winter season.MethodsIn this cross-sectional study, a random sample of naso-/oropharyngeal specimens from symptomatic adults seeking for SARS-CoV-2 molecular testing between December 2021 and March 2022 were tested for RSV and other respiratory pathogens by means of reverse-transcription polymerase chain reaction. RSV-positive samples were further molecularly characterized by sequence analysis.ResultsOf 1,213 samples tested, 1.6% (95% CI: 0.9–2.4%) were positive for RSV and subgroups A (44.4%) and B (55.6%) were identified in similar proportions. The epidemic peak occurred in December 2021, when the RSV prevalence was as high as 4.6% (95% CI: 2.2–8.3%). The prevalence of RSV detection was similar (p = 0.64) to that of influenza virus (1.9%). All RSV A and B strains belonged to the ON1 and BA genotypes, respectively. Most (72.2%) RSV-positive samples were also positive for other pathogens being SARS-CoV-2, Streptococcus pneumoniae and rhinovirus the most frequent. RSV load was significantly higher among mono-detections than co-detections.ConclusionDuring the 2021/22 winter season, characterized by the predominant circulation of SARS-CoV-2 and some non-pharmaceutical containment measures still in place, a substantial proportion of Italian adults tested positive for genetically diversified strains of both RSV subtypes. In view of the upcoming registration of vaccines, establishment of the National RSV surveillance system is urgently needed.

Burden of Influenza and Respiratory Syncytial Viruses in Suspected COVID-19 Patients: A Cross-Sectional and Meta-Analysis Study.

Non-SARS-CoV-2 respiratory viral infections, such as influenza virus (FluV) and human respiratory syncytial virus (RSV), have contributed considerably to the burden of infectious diseases in the non-COVID-19 era. While the rates of co-infection in SARS-CoV-2-positive group (SCPG) patients have been determined, the burden of other respiratory viruses in the SARS-CoV-2-negative group (SCNG) remains unclear. Here, we conducted a cross-sectional study (São José do Rio Preto county, Brazil), and we collected our data using a meta-analysis to evaluate the pooled prevalence of FluV and RSV among SCNG patients. Out of the 901 patients suspected of COVID-19, our molecular results showed positivity of FluV and RSV in the SCNG was 2% (15/733) and 0.27% (2/733), respectively. Co-infection with SARS-CoV-2 and FluV, or RSV, was identified in 1.7% of the patients (3/168). Following our meta-analysis, 28 studies were selected (n = 114,318 suspected COVID-19 patients), with a pooled prevalence of 4% (95% CI: 3-6) for FluV and 2% (95% CI: 1-3) for RSV among SCNG patients were observed. Interestingly, FluV positivity in the SCNG was four times higher (OR = 4, 95% CI: 3.6-5.4, p < 0.01) than in the SCPG. Similarly, RSV positivity was significantly associated with SCNG patients (OR = 2.9, 95% CI: 2-4, p < 0.01). For subgroup analysis, cold-like symptoms, including fever, cough, sore throat, headache, myalgia, diarrhea, and nausea/vomiting, were positively associated (p < 0.05) with the SCPG. In conclusion, these results show that the pooled prevalence of FluV and RSV were significantly higher in the SCNG than in the SCPG during the early phase of the COVID-19 pandemic.

Serological Diagnosis of Respiratory Syncytial Virus by ELISA Technique among Children with Respiratory Tract Infections in Beiji City, Iraq

The study have been done to detect Human Respiratory syncytial virus (HRSV) infections among hospitalized children under 5 years old in Beiji city Salah-Aldin Governorate, in addition to identify the risk factors associated with the virus. Whole blood samples were taken from 300 hospitalized children between the end of October 2021, to the end of June 2022, each sample was analyzed for HRSV by immunoglobulin M (IgM) specific to HRSV determining from blood specimens in serum using enzyme-linked immune sorbent assay (ELISA) technique. Of the 300 serum samples, Respiratory syncytial virus (RSV) was found in 120 (40%), 63 (42%) females, and 57 (38%) males. The age group was more susceptible to infection between 7-12 months for RSV at a rate of 25%. The study revealed that 61.66% of children exposed to smoke from one or both parents was positive for RSV, while 38.33% showed negative results for the presence of RSV. Considering the type of feeding, the current study showed that RSV infection was demonstrated in a higher percentage in patients with bottle feeding 60%, while a low percentage was demonstrated in patients with breastfeeding at 13.3%. Our results indicated the prevalence of RSV among children after imposing vaccination and reducing non-pharmaceutical interventions.

The acute bronchiolitis rebound in children after COVID-19 restrictions: a retrospective, observational analysis.

Bronchiolitis represents the main cause of illness and hospitalization in infants and young children. The aim of this study was to compare the Pediatric Emergency Department (PED) admissions for bronchiolitis during the post-COVID (Coronavirus disease) period to those of previous seasons and to analyze their etiology during COVID and post-COVID period. We compared demographics, clinical and microbiological data of children admitted to PED with bronchiolitis between September 2021 and March 2022 (post-COVID period) to the previous seasons (COVID and pre-COVID period). During the post-COVID period the bronchiolitis season started earlier than usual, with a peak reached in November 2021; a gradual reduction was subsequently observed between December 2021 and January 2022. Our data showed a prevalence of High Priority code in children admitted to the PED with bronchiolitis during the post-COVID period (61.4%) compared the pre-COVID period (34.8%) (p=0.00). Also regarding the hospitalization of these patients, we found a major rate of hospitalization during this epidemic season (p=0.035). In addition, only 4 (1.5%) of the tested children resulted positive for SARS-CoV-2 and all of them were admitted to PED during the post-COVID period. The search for the other respiratory viruses showed during the current season a prevalence of respiratorysyncytialvirus(RSV) (60.2%), followed by Human Rhinovirus (30.1%). The post-COVID period was characterized by an early and short-term peak in acute bronchiolitis, with an increased rate of hospitalization. In addition, SARS-CoV-2 infection was rarely cause of bronchiolitis in children under 2 years old.

Determining the Relationship of Meteorological Factors and Severe Pediatric Respiratory Syncytial Virus (RSV) Infection in Central Peninsular Malaysia.

Respiratory syncytial virus (RSV) is the most common pathogen causing viral respiratory tract infections among younger children worldwide. The influence of meteorological factors on RSV seasonal activity is well-established for temperate countries; however, in subtropical countries such as Malaysia, relatively stable temperate climates do not clearly support this trend, and the available data are contradictory. Better understanding of meteorological factors and seasonality of RSV will allow effective strategic health management relating to RSV infection, particularly immunoprophylaxis of high-risk infants with palivizumab. Retrospectively, from 2017 to 2021, we examined the association between various meteorological factors (rainfall, rainy days, temperature, and relative humidity) and the incidence of RSV in children aged less than 12 years in Kuala Lumpur, Malaysia. RSV activity peaked in two periods (July to August and October to December), which was significantly correlated with the lowest rainfall (p < 0.007) and number of rainy days (p < 0.005). RSV prevalence was also positively associated with temperature (p < 0.006) and inversely associated with relative humidity (p < 0.006). Based on our findings, we recommend that immunoprophylaxis with palivizumab be administered in children aged less than 2 years where transmission of RSV is postulated to be the highest after the end of two monsoon seasons.

371. Adding sputum and saliva to nasopharyngeal swab samples for PCR detection of Respiratory Syncytial Virus in adults hospitalized with acute respiratory illness may double case detection

Abstract Background In hospitalized patients, nasopharyngeal (NP) swabs are the most common samples obtained for Respiratory Syncytial Virus (RSV) PCR testing. However, adding sputum is known to increase diagnostic yield, and saliva has been successfully used for viral respiratory infection diagnosis. We sought to compare RSV prevalence detected by PCR testing of NP swab alone versus NP swab plus saliva and sputum in adult patients hospitalized with acute respiratory illness (ARI). Methods This ongoing, prospective cohort study enrolled patients aged ≥40 years hospitalized for ARI in 4 hospitals in Louisville, Kentucky (Season 1: 27 Dec 21 – 1 Apr 22). NP swab, saliva, and sputum samples were obtained at enrollment or scavenged from standard-of-care specimens (all collected ≤3 days of admission), and PCR tested with Luminex ARIES FluA/B/RSV platform. We produced Venn diagrams of RSV positive samples by sample type for all patients and restricted to those with all 3 sample types. RSV prevalence for NP swab alone was calculated as number of patients with RSV-positive NP swabs divided by total number of patients tested. RSV prevalence by NP swab plus saliva and sputum was calculated as number of patients with RSV-positive NP swab, saliva, or sputum samples divided by total number of patients tested. Results We enrolled 653 patients and collected NP swabs (100% of patients), saliva (96%), and sputum (43% overall and 93% of the 303 sputum-producing patients). Among all patients, 28 patients tested RSV positive (Figure 1A), and when restricted to those with all 3 samples (Figure 1B), 14 tested positive. The overall cohort’s RSV prevalence by NP swab alone was 1.8% (12/653) and by NP swab plus saliva and/or sputum was 4.3% (28/653): 2.33 times higher with addition of saliva and sputum samples. Among patients with all 3 specimen types, the RSV prevalence increase was the same, and none were positive by NP swab only. Figure 1.Venn diagrams of positive RSV PCR tests (Left) A. Positive RSV PCR tests for 653 patients in overall cohort (Right) B. Positive RSV PCR tests for 275 patients with all 3 samples obtained. Conclusion RSV was most commonly detected in saliva samples. Current standard-of-care utilizing NP swab for RSV PCR testing appears to underestimate true RSV prevalence in hospitalized adult patients with ARI by more than 2-fold. Disclosures Alan Junkins, PhD, D(ABMM), Biomerieux: Advisor/Consultant Paul S. Schulz, MD, Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Gilead: Honoraria|Merck: Advisor/Consultant|Merck: Grant/Research Support|Merck: Honoraria Robin Hubler, MS, Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds Paula Peyrani, MD, Pfizer, Inc: Employee|Pfizer, Inc: Employee|Pfizer, Inc: Stocks/Bonds|Pfizer, Inc: Stocks/Bonds Paula Peyrani, MD, Pfizer, Inc: Employee|Pfizer, Inc: Employee|Pfizer, Inc: Stocks/Bonds|Pfizer, Inc: Stocks/Bonds Qing Liu, M.S., Pfizer Inc.: I am a full time employee of Pfizer and hold Pfizer stocks Bradford D. Gessner, M.D., M.P.H., Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds Elizabeth Begier, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds.

Molecular detection of respiratory syncytial virus in children attending selected hospitals in Kaduna State, Nigeria

A serological survey was carried out among children in two hospitals within Kaduna, Kaduna state to determine the level of Respiratory syncytial virus (RSV) IgM antibodies. Blood samples and nasal swabs of children aged 0-60 months were collected in two hospitals in Kaduna metropolis (Barau Dikko Teaching Hospital and Yusuf Dantsoho Memorial Hospital), Kaduna state. Respiratory Syncytial Virus IgM antibody level was measured using commercial ELISA kit obtained from DEMEDITEC DIAGNOSTIC GMBH Germany. The overall prevalence of RSV out of 192 samples of both blood and nasal swab samples collected 56.1 % positive for all the samples from both hospitals. Barau Dikko positive samples recorded 26.0 % and Yusuf Dantsoho 30.0 % as shown in figure 1. More so, the distribution of RSV with regards to socio-demographic characteristics, males had a higher predominance 31.0 % than females 26.0 % but the result was not statistically significant (p value= 0.285). Infants under one month had the highest prevalence rate of 75 % while 31-61 months had the least prevalence rate of 11.0 %. The difference was statistically significant (p value= 0.001). Respiratory syncytial virus RSV-G gene was detected among IgM seropositive children using a molecular analysis. Conclusively, Polymerase chain reaction on agarose gel electrophoresis verified the molecular characteristics of the RSV-G gene, which showed a typical band size of 326bp.

Characterisation of RSV Fusion Proteins from South African Patients with RSV Disease, 2019 to 2020.

Respiratory syncytial virus (RSV) is classified into RSV-A and RSV-B, which are further classified into genotypes based on variability in the G gene. The fusion (F) protein is highly conserved; however, variability within antigenic sites has been reported. This study aimed to characterise F proteins from RSV strains detected in South Africa from 2019 to 2020. Patients of all ages, from whom respiratory samples were submitted to the National Health Laboratory Service at Charlotte Maxeke Johannesburg Academic Hospital, South Africa during 2019 to 2020, were included. Complete RSV F genes were amplified for next-generation sequencing. MEGA X software was used for phylogenetic analysis. The overall prevalence of RSV was 5.8% (101/1734). Among 101 RSV positive samples only 69.3% (70/101) were available for characterization of the RSV F protein gene. Among cases included for F gene characterisation, viral co-infections were observed in 50% (35/70) and 25.7% (18/70) were admitted to intensive care units (ICU). About 74.2% (23/31) of F gene sequences cluster with other African NA1/ON1 genotypes. At antigenic site I, the V384I mutation was replaced by V384T in South African strains. The S275F mutation was seen in a single South African strain. The N120 N-linked glycosylation site was present in 25.8% (8/31) of RSV-A F proteins described in this study. For the first time, we detected the rare S275F mutation that is associated with palivizumab resistance.

Prevalence, pattern of distribution and characterization of respiratory syncytial virus associated acute respiratory tract infections in hospitalized children less than 5 years in a general hospital in Sri Lanka from 2016–2018

Respiratory Syncytial Virus (RSV) is one of the most common respiratory viruses causing acute respiratory tract infections (ARTI) in children. Detailed data on RSV infections including the RSV types circulating in Sri Lanka are not available. This study aimed to determine the prevalence, patterns and characterization of RSV associated ARTI in hospitalized children less than 5 years in a general hospital in Sri Lanka. We tested 500 nasopharyngeal aspirate (NPA) samples collected from children with suspected viral ARTI from May 2016 to July 2018 from Kegalle General Hospital, Sri Lanka for RSV using antigen detection by an immunofluorescence assay (IFA). RSV positive samples were further characterized using the real time RT-PCR. RSV was the predominant virus associated with ARTI with a prevalence of 28% (140/500) in the study sample. RSV in was also detected in more co-infections with other respiratory viruses. RSV was detected throughout the year with peak periods from June to August 2016, March to July 2017 and May to July 2018. Of the 140 RSV positive children tested, 72.14% had RSV-B, while 27.86% had RSV-A infection. Both RSV subtypes were detected throughout the study period with overlapping patterns. A few co-infections between RSV-A and RSV-B were detected during the co-circulation. RSV was the most prevalent virus and RSV-B was the predominant subgroup associated with ARTI in the children <5 years in Sri Lanka from May 2016 to July 2018. RSV was detected throughout the study period with peaks in certain months in the study area.